Enhanced Carbon Dioxide Electroreduction to Carbon Monoxide over Defect‐Rich Plasma‐Activated Silver Catalysts

Abstract

Efficient, stable catalysts with high selectivity for a single product are essential if electroreduction of CO is to become a viable route to the synthesis of industrial feedstocks and fuels. A plasma oxidation pre-treatment of silver foil enhances the number of low-coordinated catalytically active sites, which dramatically lowers the overpotential and increases the activity of CO electroreduction to CO. At -0.6 V versus RHE more than 90 % Faradaic efficiency towards CO was achieved on a pre-oxidized silver foil. While transmission electron microscopy (TEM) and operando X-ray absorption spectroscopy showed that oxygen species can survive in the bulk of the catalyst during the reaction, quasi in situ X-ray photoelectron spectroscopy showed that the surface is metallic under reaction conditions. DFT calculations reveal that the defect-rich surface of the plasma-oxidized silver foils in the presence of local electric fields drastically decrease the overpotential of CO electroreduction.

Catalytic Hydrogen Production by Janus CuAg Nanostructures

“…Cu NPs/ZnO and Ag NPs/ZnO were also investigated for comparison . As shown in Figure a, the Ag 3d binding energies of these three Cu−Ag NPs/ZnO are approximately 367.9 eV and 373.7 eV (corresponding to Ag 0 ), while those of Ag NPs/ZnO are 367.3 eV and 373.3 eV (corresponding to Ag + ),, suggesting that the Ag species in these three Cu−Ag NPs/ZnO had an enhanced antioxidant capacity compared with Ag NPs/ZnO. More interesting, we found the similar results in the Cu 2p signals (Figure b).…”

Rational Design of Ag‐Based Catalysts for the Electrochemical CO2 Reduction to CO: A Review

“…It was also reported that structure, morphology, size, and composition of the catalyst can lead to adsorption and decoupling site preferences of different adsorbates of C bound on the surface and further result in the breaking of the linear scaling relationships and tuning of the adsorption strength, eventually exerting a dramatic influence on the ECR performance . Indeed, in addition to polycrystalline and single‐crystalline Ag, some new A types have been developed and characterized recently, such as nanostructured Ag with different sizes, supported Ag catalysts with different substrates including C, TiO 2 , Al 2 O 3 , dopant‐aided Ag, oxide‐derived Ag, and surface‐modified Ag …”

“…To get in‐depth understanding how the subsurface O and cationic metal species can tune the structure and morphology of Ag catalysts as well as further optimize reaction kinetics and pathways in the ECR to CO, Mistry et al. synthesized OD‐Ag catalysts by the treatment of Ag foils in low‐pressure plasma of O 2 gas . Compared to the counterpart metallic Ag foil, the OD‐Ag catalyst with O 2 plasma treatment displayed an FE of CO of more than 90 % at a low potential of −0.6 V versus RHE in 0.1 m KHCO 3 .…”

Facet Sensitivity of Capping Ligand‐Free Ag Crystals in CO2 Electrochemical Reduction to CO

“…The presence of oxygen in the deep bulk of o‐Ag 2 O‐5h can be related to the large size of o‐Ag 2 O that makes the electrochemical reduction of the deep bulk kinetically slow. The survival of oxygen in a silver foil pre‐oxidized by oxygen plasma during electrochemical CO 2 reduction was also observed very recently …”